Tibialis anterior surface EMG parameters change before force output in multiple sclerosis patients

Abstract

Neuromuscular function has been studied in multiple sclerosis patients with differing levels of disability. Force during maximal voluntary ankle dorsiflexion and surface EMG in tibialis anterior for weakest and strongest legs in 31 patients was compared with 16 control subjects. In the most mildly affected patients strength of dorsiflexion for the strongest leg was not significantly different from that of controls, but integrated mean EMG and median frequency of the power spectrum were significantly lower. In all other patient groups, all parameters measured were different from control values. Results indicate an important change in neuromuscular parameters which precedes loss of the ability to recruit normal force levels. Such changes may imply that the muscles of multiple sclerosis patients are affected even before there is significant evidence of neural motor dysfunction.

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References

Minderhoud JM , van der Hoeven JH , Prange Aja. Course and prognosis of multiple sclerosis. Acta Neurol Scand 1988 ; 78: 10-15.

Miller DM , Rudge P. , Johnson G. et al. Serial gadolinium enhanced magnetic resonance imaging in multiple sclerosis . Brain 1988; 11: 927-39.

Isaac C. , Li D. , Genton M. et al. Multiple sclerosis: a serial study using MRI in relapsing patients. Neurology 1988; 38: 1511-15.

Thompson AJ , Kermode AG , MacManus DG et al. Patterns of disease activity in multiple sclerosis: clinical and magnetic resonance imaging study. Br Med J 1990; 300: 631-34.

Kurtzke JF Rating neurological impairment in multiple sclerosis: an expanded disability status scale (EDSS). Neurology 1983; 33: 1444-52.

Preece AW , Preece DL , Murfin JL , Jones Rjs. On line analysis of neuromuscular function. IEEE Eng Med Biol 1988; 10: 1607.

Jones Rjs , Preece DL , Preece AW , Green JL Physiological measurement of muscle performance in multiple sclerosis. In: Gonsette RE , Delmotte P eds. Recent advances in multiple sclerosis therapy . Amsterdam: Excerpta Medica, 1989: 239-42.

Willison RG Analysis of electrical activity in healthy and dystrophic muscle in man. J Neurol Neurosurg Psychiatry 1964; 27: 386-94.

Christensen H. , Fuglsang-Frederiksen A. Power spectrum and turns analysis of EMG at different voluntary efforts in normal subjects. Electroencephalog Clin Neurophysiol 1986; 64: 528-35.

10.

Nandedkar SD , Sanders DB , Stålberg MD Stimulation and analysis of the electromyographic interference pattern in normal muscle. Part I: Turns and amplitude measurements . Muscle Nerve 1986; 9: 423-30.

11.

Cenkovich FS , Gersten JW Fourier analysis of the human electromyogram . Am J Phys Med 1963; 42: 192-204.

12.

Mills KR Power spectral analysis of electromyogram and compound muscle action potential during muscle fatigue and recovery. J Physiol 1982; 326: 401-409.

13.

Adendt-Nielsen L. , Mills KR The relationship between mean power frequency of EMG spectrum and muscle fibre velocity. Electroencephalog Clin Neurophysiol 1985; 60: 130-34.

14.

Milner-Brown HS , Mellenthin M. , Miller G. Quantifying human muscle strength, endurance and fatigue. Arch Phys Med Rehabil 1986; 67: 530-35.

15.

Jones Rjs , Rees DP , Campbell MJ EMG and force valves during sustained contraction in MS patients: implications for therapy. In: Wietholter H , Dichgans J , Mertin J eds. Current concepts in multiple sclerosis. Amsterdam : Excerpta Medica, 1991; 81-86.

16.

Rice CL , Vollmer TL , Bigland-Richie B. Neuromuscular responses of patients with multiple sclerosis. Muscle Nerve 1992; 15: 1123-32.